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ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #422202
Research Project: Novel Approaches for Managing Key Pests of Peach and Pecan

Location: Fruit and Tree Nut Research

Title: Entomopathogenic nematodes in pecan orchards in Georgia and their virulence on selected pecan pests

Author
item ACHARYA, RAJENDRA - University Of Georgia
item BARMAN, APURBA - University Of Georgia
item Shapiro Ilan, David

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Pecans are the most economically important native nut crops in the United States. Several insect pests cause damage to pecan and can reduce profitability. Chemical insecticides are commonly used to control many pecan insect pests but alternative measures are needed due to environmental and regulatory concerns. Entomopathogenic nematodes (also called beneficial nematodes) are small round worms that are used as environmentally friendly biopesticides. We tested the ability of beneficial nematodes to kill three different insect pests that attack pecan: fall webworm, nut curculio and walnut caterpillar. A variety of nematode species were tested to see which ones are most virulent (had the highest disease causing power). Two nematodes, Heterorhabditis indica and Heterorhabditis zealandica were found to be most virulent to the targeted pests. This research provides a new environmentally sustainable direction to pursue for control of several pecan pests.

Technical Abstract: Several insect pests that are prevalent in pecan orchards and cause considerable damage to leaves and nuts including fall webworm (Hyphantria cunea Drury) (Lepidoptera: Erebidae), walnut caterpillar (Datana integerrima Grote and Robinson) (Lepidoptera: Notodontidae) and nut curculio (Curculio hicoriae) (Coleoptera: Curculionidae). Synthetic insecticides are commonly used to manage these pests. However, developing effective biological control methods is essential to reduce reliance on chemical insecticides and their associated impacts. Entomopathogenic nematodes (EPNs) are effective biocontrol agents used against various lepidopteran and coleopteran pests in different cropping systems. The objectives of the current study were to identify the locally available EPNs in pecan orchards and evaluate their effectiveness against fall webworm, walnut caterpillar, and nut curculio. EPNs were recovered from all sampled orchards, with 46.43% of the samples and identified five EPN species, Heterorhabditis indica, H. zealandica, Meterhabditis rainai, Oscheius myriophilus, and Steinernema glaseri. A virulence assay indicated that H. indica and H. zealandica exhibited high virulence against both the larvae and pupae of fall webworm, walnut caterpillar, as well as larvae of nut curculio. In contrast, M. rainai, O. myriophilus, and S. glaseri demonstrated low virulence against the larvae of fall webworm and walnut caterpillar. Therefore, H. indica and H. zealandica could be potential biological control agents for managing fall webworm, walnut caterpillar, and nut curculio in pecan orchards.